Since the introduction of polyurethane wire enamel from almost 60 years ago, the interest and demand of polyurethane wire enamels has remained high. Over the years, the performance has been further and further optimized. Their main use, as coatings in the field of fine and ultra fine wire for small electrical devices and electronics, where fast solderability at low temperatures is a must, makes polyurethanes especially an important material for wire enamels today. The high copper price and the growing Asian market lead to an increasing fine wire market and, therefore, to a higher demand of...

Since polyurethanes display a softening point at high temperatures and flows under pressure and may even melt, this puts severe limitations on the useful applications of PUs. At around 100 C the properties like tensile strength, modulus etc: start to diminish and at temperatures above 200 C, thermal degradation sets in, depending again on the nature of back-bone. Chemical modifications and cross linking are some proposed ways to overcome these deficiencies. Indeed, the general approach for improvement of thermal stability of polyurethanes has been by way of chain modification with hetrocyclic...

Essentially three cross linking process are used in the polymer related industries. Two types of chemical cross linking, those employing organic peroxides or silanes, respectively are still frequently used for the improvement of polyethylene and other polymer based insulations for wire and cable.However, the advantages of radiation cross linking over the chemical process have brought about its steady growth of about 10 to 15 % annually since the mid-1970s, when high energy and high current electron accelerators became widely available for radiation processing. Moreover; energy consumption for...